A flaw was found in qemu Media Transfer Protocol (MTP) before version 3.1.0. A path traversal in the in usb_mtp_write_data function in hw/usb/dev-mtp.c due to an improper filename sanitization. When the guest device is mounted in read-write mode, this allows to read/write arbitrary files which may lead do DoS scenario OR possibly lead to code execution on the host.

Qemu emulator <= 3.0.0 built with the NE2000 NIC emulation support is vulnerable to an integer overflow, which could lead to buffer overflow issue. It could occur when receiving packets over the network. A user inside guest could use this flaw to crash the Qemu process resulting in DoS.

A stack-based buffer overflow vulnerability was found in NBD server implementation in qemu before 2.11 allowing a client to request an export name of size up to 4096 bytes, which in fact should be limited to 256 bytes, causing an out-of-bounds stack write in the qemu process. If NBD server requires TLS, the attacker cannot trigger the buffer overflow without first successfully negotiating TLS.

A heap buffer overflow flaw was found in QEMU's Cirrus CLGD 54xx VGA emulator's VNC display driver support before 2.9; the issue could occur when a VNC client attempted to update its display after a VGA operation is performed by a guest. A privileged user/process inside a guest could use this flaw to crash the QEMU process or, potentially, execute arbitrary code on the host with privileges of the QEMU process.

An out-of-bounds memory access issue was found in Quick Emulator (QEMU) before 1.7.2 in the VNC display driver. This flaw could occur while refreshing the VNC display surface area in the 'vnc_refresh_server_surface'. A user inside a guest could use this flaw to crash the QEMU process.

Quick emulator (QEMU) before 2.8 built with the Cirrus CLGD 54xx VGA Emulator support is vulnerable to an out-of-bounds access issue. The issue could occur while copying VGA data in cirrus_bitblt_cputovideo. A privileged user inside guest could use this flaw to crash the QEMU process OR potentially execute arbitrary code on host with privileges of the QEMU process.

A stack buffer overflow flaw was found in the Quick Emulator (QEMU) before 2.9 built with the Network Block Device (NBD) client support. The flaw could occur while processing server's response to a 'NBD_OPT_LIST' request. A malicious NBD server could use this issue to crash a remote NBD client resulting in DoS or potentially execute arbitrary code on client host with privileges of the QEMU process.

The Network Block Device (NBD) server in Quick Emulator (QEMU) before 2.11 is vulnerable to a denial of service issue. It could occur if a client sent large option requests, making the server waste CPU time on reading up to 4GB per request. A client could use this flaw to keep the NBD server from serving other requests, resulting in DoS.

An assertion-failure flaw was found in Qemu before 2.10.1, in the Network Block Device (NBD) server's initial connection negotiation, where the I/O coroutine was undefined. This could crash the qemu-nbd server if a client sent unexpected data during connection negotiation. A remote user or process could use this flaw to crash the qemu-nbd server resulting in denial of service.

Quick emulator (QEMU) built with the Cirrus CLGD 54xx VGA emulator support is vulnerable to an out-of-bounds access issue. It could occur while copying VGA data via bitblt copy in backward mode. A privileged user inside a guest could use this flaw to crash the QEMU process resulting in DoS or potentially execute arbitrary code on the host with privileges of QEMU process on the host.

qmp_guest_file_read in qga/commands-posix.c and qga/commands-win32.c in qemu-ga (aka QEMU Guest Agent) in QEMU 2.12.50 has an integer overflow causing a g_malloc0() call to trigger a segmentation fault when trying to allocate a large memory chunk. The vulnerability can be exploited by sending a crafted QMP command (including guest-file-read with a large count value) to the agent via the listening socket.

Qemu before version 2.9 is vulnerable to an improper link following when built with the VirtFS. A privileged user inside guest could use this flaw to access host file system beyond the shared folder and potentially escalating their privileges on a host.

VNC server implementation in Quick Emulator (QEMU) 2.11.0 and older was found to be vulnerable to an unbounded memory allocation issue, as it did not throttle the framebuffer updates sent to its client. If the client did not consume these updates, VNC server allocates growing memory to hold onto this data. A malicious remote VNC client could use this flaw to cause DoS to the server host.

The MSI-X MMIO support in hw/pci/msix.c in QEMU (aka Quick Emulator) allows local guest OS privileged users to cause a denial of service (NULL pointer dereference and QEMU process crash) by leveraging failure to define the .write method.

The qcow2_open function in the (block/qcow2.c) in QEMU before 1.7.2 and 2.x before 2.0.0 allows local users to cause a denial of service (NULL pointer dereference) via a crafted image which causes an error, related to the initialization of the snapshot_offset and nb_snapshots fields.

Multiple buffer overflows in QEMU before 1.7.2 and 2.x before 2.0.0, allow local users to cause a denial of service (crash) or possibly execute arbitrary code via a large (1) L1 table in the qcow2_snapshot_load_tmp in the QCOW 2 block driver (block/qcow2-snapshot.c) or (2) uncompressed chunk, (3) chunk length, or (4) number of sectors in the DMG block driver (block/dmg.c).